Field of the Invention (Technical Field)
The present invention relates to an improved impeller apparatus and a dispersion method for dispersing or dissolving gases and other materials into a liquid mixture.
Background Discussion
Note that the following discussion refers to a number of publications and references. Discussion of such publications herein is given for more complete background of the scientific principles and is not to be construed as an admission that such publications are prior art for patentability determination purposes.
Impeller devices for mixing gases and other materials into a liquid mixture have a wide variety of applications in industry. One of the significant limitations and technical challenges that remain with current designs is that typically a large and powerful compressor is required in order to inject sufficient gas into a liquid mixture in order to have a desired level of gas dispersion and mixing with the liquid. Also, while many liquid mixtures are insensitive to mixture with gas at high impeller rotational speeds, the useful properties of other liquid mixtures (e.g. containing organic materials or pharmaceuticals) may be destroyed if gas dispersion and mixing is attempted at mixing speeds that are too high.
For example, an algae liquid mixture in an algae reactor for consuming carbon dioxide (CO2) cannot be mixed at high speeds using conventional propeller mixers, as algae is susceptible to shearing forces and could be killed by being shredded by the blades. In addition, algae reactor vessels using CO2 spargers that bubble CO2 from the bottom of the vessels have been limited in size due to the large amount of energy required to inject enough CO2 to feed the algae before the gas bubbles rise and escape at the top of the algae liquid mixture.